Laminated glass has heretofore been generally manufactured by a process wherein a stack of at least two sheets of glass having a plastic film called an intermediate film typically a plasticized polyvinyl butylal film sandwiched between each pair of adjacent sheets of glass is subjected to evacuation, pressing and heating. Such a process, however, has involved a problem that the productivity is low and the manufacturing costs are expensive because the process requires a lot of steps and time.
JP A 63-134539 discloses a process for producing laminated glass comprising coating a film-forming plastisol based on an epoxy group-containing vinyl chloride resin on at least one surface of a first glass plate to form a layer of the plastisol on the first glass plate, laminating a second glass plate which may have a plastisol layer on at least one surface thereof onto the first plastisol film-coated glass plate with the plastisol layer or layers being sandwiched between the first and second glass plates, and heating the laminated first and second glass plates under pressure so that the plastisol fully gelates. This process obviates various steps associated with the use of a preformed plastic film, including washing, drying, cutting and conditioning of films as well as a step of pressing laminated glass plates in an autoclave, making it possible to carry out a series of manufacturing steps on a continuous production line, whereby laminated glass may be manufactured in high productivity.
In this process, however, the surface of the plastisol layer formed on a glass plate is frequently deformed owing to surface tension to form depressions. When another glass plate is laminated to the glass plates having the depressed plastisol layer, the laminated glass plates undesirably contains air occluded in the depressions of the plastic layer, resulting in the product of poor quality.
If the second glass plated is laminated to the first glass having a layer of the plastisol which is still fluid, precise positioning of the glass plates is not easy on the one hand and the plastisol may overflow out of the peripheries of the glass plates, hindering precise control of the thickness of the plastisol film, on the other hand. Those portions of the plastisol films which have bulged out of the peripheries of the glass plates must be removed at a later stage.